1. Field of the Invention
The present invention relates to a technical field of an image processing method and mainly image processing utilized in a digital laboratory system, and more particularly, to an image processing method which enables rapid and correct or proper determination of an image processing condition of each frame whereby a high-quality image can be output efficiently.
2. Description of the Related Art
Nowadays, so-called direct exposure for projecting an image on a photographic film (hereinafter, referred to simply as a film) onto a photosensitive material (photographic paper) so as to expose the image is a main technique in printing of an image photographed on the film such as a negative film or a reversal film onto a photosensitive material.
In contrast, a printer utilizing digital exposure, that is, a digital laboratory system has recently been put into practice. In the digital laboratory system, an image recorded on a film is photoelectrically read out. The readout image is converted to a digital signal, which is then subjected to various image processings so as to obtain image data for recording. A photosensitive material is subjected to scanning exposure with recording light which is modulated in accordance with the thus obtained image data so as to record an image (latent image), thereby obtaining a (finished) print.
According to the digital laboratory system, since processing of image data serves as image processing (optimization), a high-quality print which was not obtainable with conventional direct exposure can be acquired. Moreover, not only an image photographed on a film, but an image photographed with a digital camera or the like can also be output as a print. Furthermore, an image is processed as digital image data, not only a photographic print is obtained, but also image data can be output to a recording medium such as a CD-R as an image file.
Such a digital laboratory system basically includes: a scanner (image reader) for photoelectrically reading an image recorded on a film by irradiating a film with reading light and reading its projected light; an image processor for performing predetermined image processing on the image data read out by the scanner so as to obtain image data for image recording, i.e., exposure condition; a printer (image recorder) for exposing a photosensitive material through, for example, light beam scanning, in accordance with the image data output from the image processor so as to record a latent image; and a processor (developing apparatus) for performing development processing on the photosensitive material which is exposed in the printer so as to obtain a (finished) print.
In such a digital laboratory system, the image processing condition for each frame (each image) is determined by image analysis using image data (prescan data) obtained by prescanning for roughly reading out an image prior to fine scan, that is, image reading for output (hereinafter, the determination of image processing conditions is referred to as “setup”).
Moreover, in order to further improve the productivity and the working efficiency, a laboratory system dedicated to fine scan without performing prescan has been recently developed. In this system, the setup of each frame is executed by performing image analysis using image data obtained by thinning fine scan data.
The setup is conventionally performed by using only the image data of a frame of interest. In these days, on the other hand, the setup is performed by using image data of a plurality of frames in order to perform the image processing at a higher accuracy, preventing the image-quality degradation and the like due to color failure occurring in images photographed on the lawn and the like.
For example, in a certain digital laboratory system, the setup for each frame is performed by using image data for one order (normally, a roll of film). In this method, after completion of image reading for one order, the processing is executed in the order of setup, display of a monitoring image (expected finished image=simulation image) and a monitoring operation.
In this method, however, a waiting time period from the setting of a film by an operator until the start of the monitoring operation is long. Therefore, the productivity and the working efficiency are poor.
On the other hand, another way of the setup of frame can be conceived. At the time when the reading of a predetermined number of frames is finished, the setup for each frame is performed by using the image data of all the frames which have been obtained by this point of time. Thereafter, at each time one frame is read out, the image data of the frame is added to the previously readout image data so as to execute the setup of the frame. With this method, a time period until the start of the monitoring operation can be reduced, allowing the efficient operation. However, since the number of frames used for the setup is limited, the accuracy of image processing (correction performance) is sometimes lowered; for example, if the first several frames contain the successive scenes on the lawn, the color failure occurs, giving a magenta tone to the image.